1. Field of the Invention
This invention relates to a hydraulic pressure source device for hydraulic boosters, and more particularly to an improvement in a hydraulic pressure source device for hydraulic boosters, in which a regulator adapted to regulate a pressure discharged from a hydraulic pump and transmit the regulated pressure to a hydraulic booster is provided in a high-pressure oil passage which connects an input port of the hydraulic booster and an output port of the hydraulic pump.
2. Description of the Prior Art
In conventional hydraulic pressure source device of this kind, a one-way valve which is adapted to be opened when a discharge pressure from a hydraulic pump has reached a level not lower than a predetermined level is used as a regulator. Accordingly, when a kickback phenomenon occurs during operation of a hydraulic booster, i.e., when a booster piston in the hydraulic booster is pushed back from the side of a load, the input hydraulic pressure into the hydraulic booster increases, so that the one way valve provided as a regulator is closed to hydraulically lock the booster piston. Therefore, the impact occurring due to the kickback phenomenon cannot be released. In order to release the impact occurring due to a kickback phenomenon, it has been known to take such measure that an accumulator capable of lessening an increase in the pressure in a high-pressure oil passage extending between the regulator and hydraulic booster is connected to the same oil passage.
In a hydraulic pressure source device of this kind, it is general that an accumulator which is used only for accumulating pressure is connected to a high-pressure oil passage extending between a hydraulic pump and a regulator. Therefore, if another accumulator is connected as mentioned above to a high-pressure oil passage which extends between the regulator and hydraulic booster, the number of comparatively expensive accumulators in use increases, so that the manufacturing cost of a hydraulic pressure source device inevitably increases to a considerable extent.